For finding a satisfactory compromise among rapid processing, low-waste processing, and image quality improvement by a sharpness increase due to antihalation and crossover cutting effects, various measures have been taken for increasing the rate of discharge of the dyes in the antihalation layer and crossover cutting layer out of the system during rapid processing.
JP-B 8333/1974 representing the technology of the early years discloses the use of water-soluble dyes in anti-halation layers. JP-A 70830/1987 and 126645/1989 disclose the use of dye-mordanted layers for crossover cutting.
JP-B 5574/1976 and JP-A 172828/1989 disclose the use of solid dispersions of water-soluble dyes as antihalation layers and crossover cutting layers. Also, the technique of causing dyes to be adsorbed to solid particle dispersions, especially silver halide fine grain crystals, and using them in crossover cutting layers and antihalation layers is disclosed, for example, in JP-A 29641/1990, 73336/1989, 194251/1988, 46438/1988, and JP-B 20688/1996.
The above-referred JP-A 172828/1989 describes solid dispersions of dyes, and JP-A 126645/1989 describes crossover cutting layers in which dyes are affixed with mordants. The technique of increasing the absorption of spectral sensitizing dyes is also well known in the art.
Since these techniques are based on the concept that the photosensitive element is prevented from residual color by dissolving coloring matter into processing solution, the photosensitive element should have a relatively high swelling factor. Since the photosensitive element carries the colored solution of the preceding bath to the subsequent bath, the potential problems of coloring of the processing solution and deposition of dyes become revealed with the advance of low-replenishment, low-waste and rapid processing. In particular, the solid dispersion of an alkali-soluble dye described in JP-A 172828/1989 reveals the problem of precipitation in solution and on rollers if it is carried over to the fixing and subsequent steps.
An aluminum-containing hardening fixer must be of low pH design set at pH 5 or lower for the stabilization of aluminum ions. For such a fixer, the automatic processor must be equipped with a duct for removing the odor of sulfurous acid and acetic acid. If the fixer is designed as a non-hardening one free of aluminum ions in order to solve the odor problem, the drag-out of the fixer by the photosensitive element is increased so that more of the dye to be dissolved out for decolorization by fixing treatment may be carried over to water washing and subsequent steps, eventually increasing the dye deposit in the washing tanks and on rollers.
For these reasons, it is impossible in the state-of-the-art to further reduce the replenishment and waste of processing solution and to further improve the quality of images by increasing sharpness.
On the other hand, solutions for use in processing photographic black-and-white silver halide photosensitive elements, for example, developers and fixers, especially fixers give oft odor and corrosive vapor which are serious factors detrimental to the environment where the processor is located. In the prior art, a forced ventilation duct is attached to the processor for forcedly discharging the gas, or the gas is passed through a filter of activated carbon or the like to remove odorous components. A number of automatic processors of the forced ventilation design and processing systems having such processors built therein are now commercially available, for example, under the trade name of CEPROS 30, CEPROS M2, CEPROS S, and CEPROS P from Fuji Photo Film Co., Ltd.
From the standpoint of reducing odor, it is known to set a fixer at pH 4.5 or higher for suppressing the generation of sulfurous acid gas. It is also known that aluminum ions commonly used as the hardening agent in the fixer are more likely to precipitate as the pH of the fixer becomes higher. Although this problem may be solved by removing aluminum ion as the hardening agent, the absence of aluminum ion leaves the film swollen at the end of fixation so that the photosensitive element may have a very high water content at the end of water washing, becoming an obstruction against rapid processing within 90 seconds from development to drying.
A substantial decline of the fixer concentration is also effective for reducing odor, but at the sacrifice of fixing capability, especially a fixing rate. This is especially outstanding in medical radiographic photosensitive elements which are required to have high sensitivity. Since the radiographic photosensitive elements have a relatively high silver content and mostly use silver iodobromide emulsions in order to achieve a high sensitivity, they cannot be fixed at a low concentration of fixing agent.
Rapid drying is possible with the non-hardening fixer if the photosensitive element has previously been hardened to an excessive degree as typified by a swelling factor of up to 130%. However, the swelling of the photosensitive element during development and fixation is also significantly suppressed, leading to several undesirable problems including a sensitivity decline, a loss of covering power (blackening density per unit quantity of developed silver), worsening of residual color, and short fixation.